Virgin Australia along with their codeshare partner Delta are offering cheap flights to the US. Qantas is also matching the prices on some of the routes. Nothing beats NY especially at $845 however DC and Chicago are great destinations. Was in Chicago last summer and was great. Just don't go in winter.
Fares include bags, meals, seats. A couple of layovers on the way. Dates range from January to August 2018.
Find the flights in Google Flights then use Skyscanner, Momondo, IWTF or whatever to book your flights. Skyscanner isn't picking up all of the cheap flights. If that's the case use one of the other booking sites.
Sydney to Aspen, Colorado $856 - Google Flights - Example Skyscanner fare
Sydney to Chicago, Illinois $853 Qantas - $860 VA/Delta - Google Flights - Example Momondo Fares $860 via VA - IWTF via Qantas $853
Sydney to Denver, Colorado $846 - Google Flights - Example Skyscanner Fare
Sydney to Washington D.C. $860 - Google Flights - Example Momondo Fare
Sydney to Houston, Texas $860 - Google Flights - Example Momondo Fares - The Houston Rodeo is worth it if you go in March.
Also, if you are OK to fly with United, they are offering flights to Miami for $950
I'd avoid the United flights… they are the worst airline to USA, having flown with them, Qantas, Air NZ and Virgin to the USA. Great prices to non-California cities.